1. Field of the Invention
The present invention is generally related to a cone material in endodontic treatment, and more particularly to a thermoplastic polyurethane-based cone material in endodontic treatment.
2. Description of the Prior Art
The purpose of root canal treatment is to create an end result where the tissues that surround a tooth's root will maintain a healthy status despite the fact that the tooth's nerve has undergone degenerative changes. Root canal treatment occurs in three stages: First comes the diagnosis. Next comes the root canal itself, in which a dentist or an endodentist (a dentist who specializes in treating the inside of the tooth) removes the pulp (and thereby the infection), and cleans the inside of the tooth preparatory to filling it, sometimes applying antibiotics to thwart further infection. A temporary filling is placed at the crown opening. Finally, in a subsequent appointment, a crown is installed to seal the tooth and protect it from further damage or infection.
Root canal obturation involves inserting a filling cone into a root canal and cementing it therein to obturate the canal using a sealer. The common root canal filling cone material is made from gutta-percha or resilon. Lateral condensation and vertical condensation of warm or hot gutta-percha/resilon are methods be used in sealing root canals. After cementing a primary cone short of apex of the root canal, heat application is alternated with a series of smaller and smaller pluggers until the gutta-percha or resilon is moved to the apex.
The traditional root canal material is inert in nature and will not be absorbed or degraded by living tissue if the root canal is overfilled and extends beyond the apex. It has been a challenge for dentists to control the exact amount of the material within the border of the root canal to avoid overfilling. The cold core of the root canal material is not malleable so that it cannot be molded to the canal walls, resulting in poor adherence. In addition, when heated the root canal material cools to body temperature in the root, a uniform contraction takes place further reducing adherence to the root canal walls. Moreover, the filling is a polyisoprene rubber material in nature, which does not have the capability to bond to most dental materials, especially when the root canal sealer is a polymer-based material. Due to poor adherence and bonding, bacteria residential in the root canal can multiply or a leakage may result, causing bateria to enter the canal from the mouth, which can lead to the persistence of an infection or other complication. According to the above, it is important to develop a novel set of root canal material which has high biocompatibility, low volume contractive rate, better chemical-bonding ability with dentinal wall and the filling and high mechanical properties.